High crystallinity oligo(3-methylthiophenes) for p-channel organic field-effect transistors

A new type of oligo(3-methylthiophenes) with highly regiosymmetric chemical structure was presented for developing high performance and solution-processable organic field-effect transistors (OFETs). The representative molecule Br4MT, tetramer of the oligo(3-methylthiophenes), was synthesized through the oxidative cross-coupling reactions using Cu(II)-catalyst and fully characterized. The Br4MT exhibited remarkably high crystallinity and great ionization potential due to its unique molecular structure, evidenced by differential scanning calorimetry, electrochemical and X-ray diffraction studies. The solution-processed OFETs based on Br4MT achieved high hole mobility of up to 0.24 cm²/V/s with reasonable ambient stability, suggesting that the Br4MT had great potential for application in low-cost OFETs.